Non-progressive demountable partitions have been constructed heretofore with partition corners which are formed by extending one of the two walls forming the corner all the way to where the wall corner is desired and then abutting the end of the second wall against the side of the first wall, adjacent the end of the first wall. Preferably, the two walls would abut such that the wallboard on one side of the second wall overlapped the end of the first wall. A small angular elongate corner trim would then be affixed over the ends of the boards at the corner.